A passive optical network (PON) can deliver voice, video and data services among multiple network nodes, often referred to as optical network terminals (ONTs), using a shared optical fiber. Passive optical splitters and combiners enable multiple ONTs to share the same optical fiber link. For example, downstream information carried by the shared optical fiber link may be optically split for transmission to multiple ONTs via individual optical fibers. Likewise, upstream information received from individual ONTs via individual optical fibers may be optically combined for transmission via the shared optical fiber link. An ONT, sometimes referred to as a subscriber premises node, may be connected to one or more subscriber devices, such as televisions, set-top boxes, telephones, computers, or network appliances, which utilize voice, video and data services delivered via the PON.
A PON typically includes a PON interface, sometimes referred to as an optical line termination (OLT), which may have multiple PON interface modules. The PON interface modules serve respective optical fiber links. An OLT provides an interface for downstream transmission and upstream reception of information over a shared optical fiber link that serves a group of ONTs. The OLT may be coupled to an optical splitter/combiner via the shared optical fiber link. A PON is inherently a downstream-multicast medium. Each downstream communication on the shared optical fiber link can be received by every ONT served by that link. ONTs may identify selected packets or frames on the optical fiber link based on addressing information included within the packets or frames. In addition, individual ONTs transmit upstream packets to the OLT via the shared optical fiber link.